Résumé : A regional conference on the “Ecology and Impact Assessment of Phaeocystis Blooms in the Eastern Channel and Southern Bight of the North Sea” was held in Oostende, Belgium, November 27–29, 2002 at the initiative of the Belgian SPSD2 (second scientific support plan for a sustainable development policy, Belgian Federal Science Policy Office) project AMORE (Advanced MOdelling and Research on Eutrophication) and the French “Chantier Phaeocystis” of PNEC (Programme National sur l’Environnement Côtier).